keys-for-li-elements-why-its-needed
Keys in React are utilised to identify specific Virtual DOM Elements that have changed. The classic example of usage of keys is a list. Keys are important when rendering collections of items in ...
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What are the approaches to include polyfills in your create-react-app?
What are the approaches to include polyfills in your create-react-app? There are approaches to include polyfills in create-react-app, Manual import from core-js: Create a file called (something ...
history.push
this.props.history.push("/") Official DocEffectively this is the most common way to implement redirect after a successful form submission. Use case in my MERN book library repoonSubmit = ...
Functional-component-declaration-syntax
Converting a class-based component to Functional Componentclass TableRowWrapper extends Component { render() { return <tr>{this.props.children}</tr>; } }Now the ...
e.target.value
The most common implementation of this is as follows to capture the change of event for typing in a form (a login form for example)handleChange(event) { this.setState ({ : ...
What is destructuring in the context of React
Very simply its passing an object as an argument to the function, but the destructuring uses only the named properties of the object.const destructuring = ({ used }) => console.log(used); ...
destructuring_basics-js
Without using the destructuring syntax getting multiple values out of an array can be quite cumbersome. You would do something like this:const items = ;const car = items; const bike = ...
Controlled-unContolled-Component
A large part of React is this idea of having components control and manage their own state. What happens when we throw native HTML form elements (input, select, textarea, etc) into the mix? Should we ...
Implementing this React context API
One simple use case for implementing this React context API Have you ever experienced the pain of trying to get state from the top of your react tree to the bottom? This pain you’re feeling is ...
What is reconciliation
React is magical, but it still can’t get around the fact that we must build a DOM for the user to see anything. Building a DOM on every page load is not really faster than old-fashioned HTTP calls ...
What is DOM rendering – Virtual-DOM-and-Reconciliation-Algorithm
The virtual DOM is a tree based on JavaScript objects created with React that resembles a DOM tree. Each time you need to change something in the DOM, React employs a different algorithm that ...
Redirect Component
Rendering a will navigate to a new location. The new location will override the current location in the history stack, like server-side redirects (HTTP 3xx) do. ...
React Fragment
All return values need to be wrapped in a div. This is because a component can only return one single element, and if you want more than one, you need to wrap it with another container tag. This, ...
Explain-whats-wrong-with-this-React-code
Technical interviews may also include time where the developer is asked to look at (and probably write) some code. Hence, take a look at the code below. Can you identify two problems ?class ...
Create-Class-avoiding-binding-in-constructor
Standard way to define classclass Counter extends Component {constructor (props) { super(props)this.state = { counter: 0, }// I have ...
Refs-and- key- in-React
First off, let me express that this is generally not the way to go about things in React land. Usually what you want to do is pass down functionality to children in props, and pass up notifications ...
Redux Source Code
Lets look at the Redux Source Code https://github.com/reduxjs/redux/blob/9d3273846aa8906d38890c410b62fb09a4992018/src/combineReducers.ts#L197let hasChanged = false const nextState: ...
What is Snapshot testing
A cool feature that Jest has is snapshots. This takes a snapshot of your component and how it renders and then will compare that whenever doing other tests to let you know if something unexpected is ...
Shallow Renderer
When writing unit tests for React, shallow rendering can be helpful. Shallow rendering lets you render a component “one level deep” and assert facts about what its render method returns, without ...
Styled-component
The main thing you need to understand about Styled Components is that its name should be taken quite literally. You are no longer styling HTML elements or components based on their class or HTML ...
